(a) field of the invention
This invention is in the field of Dentistry study appliances and study methods for correcting irregularities in the position and alignment of teeth in the mouth of the patient and also deals with the combination of such appliances with mounting apparatus for mounting an artificial model of the teeth simulating those of the patient in order to study the occlusion and the articulation of the model and to reproducably monitor the orthodontic treatment.
(B) DESCRIPTION OF THE PRIOR ART
(1) prior Apparatus
Williams, U.S. Pat. No. 1,485,657, granted Mar. 4, 1924 discloses a dental articulator in which upper and lower model supporting members are relatively adjustable to obtain, in the practice of prosthesis, the proper position of the teeth on one model in the occlusal plane relative to the other model. Comparison may be made with the one model, the upper has been moved, after those in the other model have been arranged according to given measurements and calculations, thus the Williams device can serve for movement of the lower teeth to give measurements and calculations after the movement has been accomplished. Alternatively, the Williams device may be used to plan movement in order to reach the desired positioning of teeth in the upper and lower set.
The purpose of the Williams dental articulator is to provide certain movements and adjustments of the cooperating upper and lower tooth model parts which greatly facilitate its use in positioning these uppers and lowers before treatment is started or to monitor treatment while it is going on or after it is finished. Because the position of the teeth in the x and y planes can be accurately controlled and charted with the Williams device, the use of this device will promote the accuracy of the dental work in which it is employed.
It is, however, ackward to use the Williams geared articulator with stone models based upon impressions of the teeth and a very high degree of skill is required for the Orthodontist to painstakingly chart the movements in the x and y plane for the present intermediate and desired tooth positions in each of the upper and lower sets.
In my U.S. Pat. No. 3,787,979, an Orthodontic Study device is provided wherein the position on each tooth may be universally adjusted. The tooth, in for form of a crown, is connected by a ball and socket joint to one end of a post which is secured at its other end to a supporting base plate. The post is in the form of elongated telescopic members whereby the height thereof may be adjusted. The post is secured to the base plate by a ball and socket joint whereby its position may be adjusted.
My Orthodontic Study device will serve to provide a precise replica of each tooth in each set, upper and lower, of the patient and will also serve to monitor positions of each tooth in intermediate and finished stages of orthodontic treatment. However, the mechanism for locating and moving the assemblies of upper and lower models in the x, y and z directions is required in order to provide the full scale utilization of my three dimensional study device in my aforesaid patent.
Wollney et al, U.S. Pat. No. 3,646,680, granted Mar. 7, 1972, presents an Orthodontic Force Model for demonstrating the direction of tooth displacement in response to externally applied forces. The Wollney apparatus is a system of springs which maintain a tooth model suspended in space. Forces are applied to this model and the direction in which the tooth is displaced as well as the amount of displacement are recorded and measured.
These forces based upon springs in Wollney can be estimated from positions in my own Orthodontic Study Model if there were available a mechanism to achieve x and y movements as in Williams, U.S. Pat. No. 1,485,657, but there would still be the requirement to achieve a tilting movement in the z direction (vertical) absent in the Williams construction.
The panoramic tripod head of the Leitz Company, known as the Tiltall Tripod and that of Peterson, U.S. Pat. No. 2,461,175, granted Feb. 8, 1949, are swiveling mechanisms which provide the free rotations and tilting movements required for panning in photography.
If the Williams articulator in U.S. Pat. No. 1,485,657 were to be combined with my prior U.S. Pat. No. 3,787,979, one would have an adjusting mechanism for bringing the lower and upper dental arch into position in respect to the x, y and z axes, but one would not have the ability to adjust the angle of tilt required by the jaw bone structure so that one would make calculations and measurements for planning treatment and for establishing the diagnosis without having the unique tilt of the jaw structure and the positioning of the teeth relative to the jaw bone structure as the factor which will permit achieving the desired bite.
Accordingly, the requirement for a proper and true understanding of the geometry of each of the teeth goes beyond the combination of my prior study model with the aforesaid Williams patent, particularly since the jaw structure is tilted and the relationships of the teeth and the upper and lower dental arches must be defined in precise relation to the existing jaw structure, the bite, the head structure, etc., all of these determined by X-ray. The deficiencies of a simple mounting of my three-dimensional or Stereodont Model of my aforesaid patent in the Williams articulator will be overcome by utilizing a triad of my new bite registration guide and complete coronal assemblies, this triad mount in my new geared articulator is characterized by a swiveling mechanism for free tilting movement in an entirely new relationship which permits extremely accurate measurement and charting as good as or better than the mst accurate micrometric measurements using an accurate measuring microscope.
(B.sub.2) PRIOR ART ORTHODONTIC PROCEDURES
The process associated with routine orthodontics consists of the following steps:
Step 1: It is routine for the Orthodontist to send to the laboratory the usual standard Alignate Impressions of the teeth of the patient. In the routine prior art practice, the laboratory pours its impression in white stone, trims, polishes, labels it and sends it back to the Orthodontist as the "Stone Model" of that patient. This is a routine procedure familiar to all who have been fitted in prosthetic dentistry.
Step 2: The stone model of the patient for the uppers and the lowers is placed in an articulator and a record is made of the position of each of the teeth.
Step 3: A dental arch representing the ideal arch for the patient's dimensions is superposed over each of the stone models in order to estimate the displacements of the teeth which require movement.
Step 4: A plan for the treatment is set forth based upon Steps 1, 2 and 3 above reflecting the condition of the patient and best judgment of the Orthodontist.
Laborious hand measurements of each of the teeth and detailed charting for planning tooth movement are essential aspects of the careful examination of the stone models and the charting procedures in Steps 2, 3 and 4 above in the prior art.
(C) SUMMARY OF APPARATUS INVENTION: NEW APPARATUS FEATURES
(1) bite registration guide
in carrying out a basic alteration of the above conventional orthodontic procedures, my invention contemplates the creation of a bite registration guide which starts with the stone models but which adds the following steps:
(a) From the stone impressions of the patient in Step 1, the laboratory pours a second stone model, but this time the model is made of the crowns of the teeth only. Thus the first model is the complete repleca while the second is a crown model. PA1 (b) While the stone is still soft and before it sets, a coronal sphere is embedded in each crown with the post held uprights until the stone sets, to provide support for the stereodont mountings. PA1 (c) The individual crowns are now removed from the alginate impression and are trimmed. The laboratory man selects one Stereodont base containing the apical ball and sockets and their posts (apical assemblies) to mount these in the crown model prepared in (b) above. PA1 (d) The laboratory man inserts each coronal assembly into its corresponding apical assembly to produce the upper and lower stereodont assembly mounted on the crown model. PA1 (e) The Bite Registration Guide. A bite registration blank comprising a piece of laminar acrylic ester or vinyl chloride paste polymer plastic 1/8 inch thick having the general parabolic contour of the dental arch, but smaller in width, is provided in at least three different sizes for corresponding different sizes of dental arch encountered in practice. PA1 (f) After the proper size of bite registration blank is selected and fits loosely along the lingual aspects of the teeth in the original model of the patient's malocclusion, the blank is now converted into the guide by the following steps: PA1 (1) send alginate impression to laboratory; PA1 (2) pour white stone into alginate impression to produce only the tooth crowns; PA1 (3) embed coronal spheres with supports upright in white stone until set; PA1 (4) removal crowns with embedded coronal spheres and supports from alginate impression and trim; PA1 (5) assemble coronal and apical units on model base; PA1 (6) make bite registration template; PA1 (7) assemble completed registration template to model; PA1 (8) align crowns on model with completed bite registration template according to patient's malocclusion; PA1 (9) send model to orthodontist; and, PA1 (10) orthodontist assembles completed model on articulator and proceeds with diagnosis and treatment planning.
(1) Paint the lingual surfaces of the teeth in the model with separating medium. PA2 (2) Pour a thin layer of self-curing acrylic (mixed monomer and polymer) on the lingual surfaces of the teeth. PA2 (3) Bring the bite-block blank into alignment and contacting the poured acrylic. PA2 (4) Hold the blank in position until the acrylic sets. PA2 (5) Remove the bite registration blank and trim it. This plate how now impressed on its periphery, the lingual surfaces of the teeth as they are in the original malocclusion. This plate is called the bite registration guide and is now clamped to the post of the rack and pinion assembly of the stereodont.
The bite registration guide prepared in accordance with the above steps is provided with a mounting slot or opening in a center portion thereof and provides two aspects of a dental arch of the patient, the first aspect representing actual lingual aspects of the teeth in the original model of the patient's "malocclusion" (see for instance paragraph f above) and in another aspect the bite registration guide provides the ideal dental arch which conforms to and is related to the specific malocclusion.
(2) MICROSCOPE LIKE MOUNTING FOR GEARED ARTICULATOR WITH HINGED PORTION ADAPTING MOUNTING
An important feature of the invention is the mounting of the bite registration guide and the teeth which are removable teeth of the stereodont to reconstruct the original malocclusion to thereby provide a model of the upper and of the lower of the patient, the upper having its own bite registration guide for the lingual surfaces of the upper arch and the lower having the bite registration guide for the lingual surfaces of the lower to thereby provide actual and ideal arches in the guide for upper and lower in a mounting in microscope like mounting for geared articulator with hinged portion adapting mounting.
In short the microscope like mount differs from the ordinary microscope in being mounted with a hing which permits the entire mounted construction to be opened, the elongating elements of the stereodont each precisely placed, each bite registration guide being mounted through its mounting slot on a pin and the assembly of microscope mounting and enumerated components closed to produce an exact replica of the teeth in the X, Y, Z measurement space which is contributed by the articulator.
The simple mounting steps place each element for orthodontic treatment in a precise relationship for actual to ideal arch in X, Y, Z space and thereby permit, for the first time, measurements using the bite registration guide as template for monitoring planning and concluding orthodontic treatment.
(3) TILTING TABLE FOR ADJUSTMENT TO JAW ANGLE
An important aspect of the invention is the tilting table which is part of the microscope like mounting because only by control of the tilt of the table on which the bite registration guide is mounted can the movement of each tooth in the direction of angular tilt corresponding to jaw angle be correlated for all of the teeth in the lower arch and for all the teeth in the upper arch. This tilting table has its most important advantages achieved in practice as a result of reversal mounting for bite registration guide.
(4) REVERSIBLE MOUNTING FOR BITE REGISTRATION GUIDE
A single post mounting served for positioning the bite registration guide in relation to the separately mounted teeth of the stereodont. Reversal of the bite registration guide effects a change in the positioning of the teeth from the actual malocclusion to new positions for each of the teeth corresponding to the ideal arch; one side of the bite registration guide corresponds in form to the lingual surfaces of the malocclusion while the other side is the outer boundary of the ideal arch.
All the foregoing steps may be carried out by the laboratory technician who can carry out the following steps with the plate which is called the bite registration guide, step a, is positioned and is now clamped to the post of the Rack and Pinion assembly of the Stereodont. Thus positioned on the stereodont, the bite-registration serves as a guide to position the movable teeth of the stereodont, thus reconstructing in the stereodont the original malocclusion.
Step b: The laboratory man positions the bite registration and arranges the teeth accordingly. This assembled and organized reproduction of the malocclusion is sent to the Orthodontist.
Step c: The Orthodontist simply attaches the received stereodont to his geared articulator and proceeds with the diagnosis and treatment planning.
(D) SUMMARY OF THE INVENTION
The process invention as illustrated in the drawings herein comprises the following steps of instruction and operation to the orthodontist or his assistant:
As shown in the drawings the assembly of the coronal and apical units on the model base bring together the Stereodont Orthodontic Study Model of my U.S. Pat. No. 3,787,979, granted on Jan. 29, 1973 into x, y and z space for very accurate positioning of each of the units in respect to the dental arch of the patient. At this stage a full jaw X-ray will serve to monitor and verify the x, y and z locations.